Sometimes System.Runtime.InteropServices.COMException (0x80080005)

I am calling a Function of a Service from a homepage. The strange thing is, this works for hours, then I do not change anything and suddenly I get the following exception:

System.Runtime.InteropServices.COMException (0x80080005): Retrieving the COM class factory for component with CLSID {00020906-0000-0000-C000-000000000046} failed due to the following error: 80080005.

Then it doesn't work anymore. When I restart the server, it works again. I am pretty sure that this is a setting in the dcom config of the Service, but I already tried everything.